hey everyone,
I got a new 670 street avenger carb, I was having fuel issues and have finally sorted them out. my problem now is my idle is fluctuating. I got my float levels set correctly, and my regulator is allowing 5.5 psi to carb, which is right where i want it. I double checked vacuum lines and feel suction on both valve covers, so don't think its my manifold gasket. I have one vacuum line not connected, but its for my heater core. I start my car and it idles great. When i put it in gear it drops too low, so i had my friend hold the brake, with car in gear, and adjusted the idle and timing. when it idles correctly in gear i have him put it back in park. the idle will sometimes go way too high and sometimes way too low. At one point i got it idled correctly in park and when he dropped it in gear it idled perfect as well. After about 4 or 5 seconds of celebration the idle went way up, i actually thought he was giving it gas. My friend said he did notice the oil pressure fluctuating but it had more oil pressure when it idled high and less when i idled too low. I thought that was normal but he has me second guessing. i guess short story long is, could it be the heater core vacuum? or could my oil pressure have something to do with it? I have even heard my valves could be too tight, doesn't seem like that would be it, but im open to suggestions. thanks in advance

 

I have a 71 350 with aluminum heads and a cam rpm intake and 670 holley street avenger carb, electric choke and VS. I still have the red fast idle on there, should i go with a different cololr? Also I adjusted timing without a vacuum so i know it isn't perfect, and my TV cable isn't hooked up to my 200r4. Don't think the tv cable would affect anything while i'm not driving, but figured i would give more info on car since first post was all info on problem. thanks again

 

This would be your problem...if it's not connected at the carb.

take off ALL of your vacuum lines. Plug the ports on the carb and intake (you should be ok leaving the brake booster hooked up). Run the car. This should cure your low idle and surging. Then start reconnecting the lines one at a time, seeing how the car reacts between each one. You should be able to narrow it down.

Also, run a vaccum gauge on the intake/carb. You should be pulling 20" at idle or so. 25+ at higher RPM.

 

I'm assuming you're running a non computer controlled distributor. If so, check your timing with it in neutral and in gear at those different rpms. If your mechanical advance is starting to advance around your idle speed, it will increase advance at say, 800 rpm but retard timing if it drops down to say, 600 rpm. Check your timing at different rpms with vacuum advance disconnected and see how it behaves. If this is the case, try some stiffer springs that keep the timing steady around the idle rpm range.